Substantial decreases in mortality in 2020 from the usual big killers, including cancer, heart disease, and chronic lung diseases, ended up swamped by deaths from COVID-19, researchers from the National Center for Health Statistics (NCHS) confirmed.

Overall life expectancy in the U.S. declined 1.5 years in 2020 versus 2019, from 78.8 to 77.3 — by far the biggest decrease in a single year since the Second World War. The 2020 figure was the lowest since 2003.

And as you might expect, COVID-19 was largely responsible for the decline, accounting for 74% of the negative contributions to American longevity, according to full-year 2020 data summarized in a Vital Statistics Rapid Release from NCHS.

Accidental injuries — a category that includes drug overdoses — were responsible for just under half of the remaining negative contributions. Fatal overdoses accounted for about one-third of that. Other, relatively minor negatives included increased early deaths from homicide, diabetes, and liver disease.

Balancing those were decreases in death rates from cancer, chronic lower respiratory diseases (such as COPD), heart disease, suicide, and perinatal conditions. Improved cancer outcomes were responsible for 45% of all contributions to increased longevity.

Of course, these trends were not identical for the two sexes nor for the major racial categories. As has long been the case, longevity for non-Hispanic Black Americans was substantially lower than for white or Hispanic people, and men on average aren’t expected to live as long as women. Moreover, the drop in life expectancy from 2019 seen overall was exaggerated for Hispanic and Black Americans (3.0 and 2.9 years, respectively) compared with white Americans (1.2 years).

While Hispanic Americans generally have longer life expectancy than Black or white Americans, they had the largest decrease in life expectancy last year, from 81.8 years in 2019 to 78.8 years in 2020.

The overwhelming influence of COVID-19 was not unexpected, with 365,000 deaths recorded in 2020 (now topping 600,000). An NCHS life-expectancy analysis based on the first 6 months of 2020 had already showed a 1.0-year decline from the same period in 2019.

Although nearly 60% of COVID deaths thus far were in people ages 75 and older — those who, to put it crudely, had already beaten the odds given when they were born (life expectancy in 1945 was roughly 65) — the flip side of that is that more than 40% were younger, and their deaths weighed negatively on longevity. Moreover, demographics for fatal overdoses, which recent CDC data for 2020 put at more than 93,000 — an all-time high — skew younger and thus have an outsized effect on life-expectancy calculations.